Agricultural harvesters are designed to travel through agricultural fields harvesting crops. They include a self-propelled combine vehicle connected to an agricultural harvesting head (also called a “header”) mounted on the front of the combine.
The head is elongate and extends perpendicular to the direction of travel of the combine. The function of the agricultural harvesting head is to sever the crop plants from the ground, to carry the cut crop material laterally inward to a central portion of the header, and then to convey the cut crop material rearward through a hole in a central rear wall of the header. Once the cut crop material is passed through the hole, it is received in the combine for further processing.
The agricultural harvesting head uses two side conveyors (typically auger conveyors or an endless belt conveyors) to draw the material laterally inward from both sides of the harvesting head to a central region of the head. A second conveyor then receives the cut crop material and conveys it rearward through the hole in the head.
In one common arrangement (often called a “draper”), the conveyors are endless belt conveyors. Each of these conveyors comprise an endless belt that is supported at opposing ends for recirculation about a drive roller and an idler roller. The drive roller is mounted close to the center of the header. The idler roller is located near an outermost lateral and of the header.
Cut crop material is deposited on the upper surface of the endless belts of the left side conveyor in the right side conveyor and is carried laterally inward to a central region of the head.
The endless belt reverses direction as it passes over the drive roller and recirculates back to the idler roller underneath the upper, crop-carrying surface.
One type of endless belt has cleats that are fixed to the outer surface of the belt. These cleats are approximately 25 mm wide, and extend 25 mm above the surface of the belt. They are made of elastomeric material and extend across the web of the endless belt in a direction perpendicular to the direction of travel of the belt. The web of the endless belt is approximately 1 m wide, and each of the cleats as a length that extends across substantially the entire width of the web of the belt.
One problem with this web+cleats arrangement is the damage done to the cleats. The damage is not done when the cleats are facing upward on the upward, crop carrying surface of the endless belt. The damages done when the endless belt is recirculated from the drive roller back to the idler roller. In this downwardly facing and dangling position, the cleats drag against frame structures that are underneath the endless belt. These frame structures wear the cleats and even tear the cleats loose from the web.
One solution to this problem, shown in US 2008/0276591 A1, is to replace the elastomeric top portion of each cleat with a dense polymer that extends the entire length of every cleat, thus providing each cleat with an elongate, slippery, polymeric strip at the top of the cleat. No matter what structure the cleat drags against underneath the endless belt conveyor, the polymeric strip with its inherent low friction, will protect the cleat.
Unfortunately, this also reduces the effectiveness of the cleats when they and their upwardly facing direction, supporting cut crop material, and carrying the cut crop material to the center of the agricultural harvesting head. Providing a high molecular weight, low friction polymer along the length of all the cleats means that friction between the cleats and the cut crop material is also reduced. Cut crop material carried on the top surface of the endless belt conveyor no longer grips the cleats, but tends to slide along the top surface.
Another solution is to provide a smooth painted metal strip underneath the endless belt in which the metal strip extends from the drive roller to the idler roller. The paint is rapidly worn, and the underlying metal surface rusts, thus causing the cleats to wear.
Another solution, provided on draper headers made by MacDon (of Canada) has been to has been to provide an elongate strip with a spray graphite coating underneath the endless belt extending from the drive roller to the idler roller such that the cleats slide along the elongate strip with reduced friction due to the graphite. Unfortunately the graphite wears off and needs replacement.
What is needed is an agricultural harvesting head of the draper type that reduces wear and damage to the cleats, while still providing sufficient friction between each cleat and the crop mat
It is an object of this invention to provide such an arrangement.